i searched the forums and everything and i looked at my ujoints and stuff.. but still im stumped.. soo im posting a vid to see wat u guys think... i really dont knoe wat it is .. thankss my car is a 85 gs wit a 83 gsl rearend

http://www.youtube.com/watch?v=zzCDBgQDgVg

 

this problem started happening about a month after da swap and now its getting louder and louder.. the sound is gone when i accelerate and it shows up when i lett off the gas.. thankss

 

LSD is bad for you. Don't do drugs. JK Even though you checked, it still sounds like the u joints. But if there's no vibration associated with it, I'm also stumped. I had u joints on my truck that were so bad you couldnt tell just by twisting the driveshaft by hand, but when they got to a certain rpm you could hear them sqeaking and grinding, but when you let off it vibrated pretty bad. Maybe have a shop check them out, when its up on a lift or something.

 

Also have you taken the diff cover off to inspect the internals. Look for signs of wear or pieces of metal.

 

I dont have sound here at work but I'll watch the vid when I get home.

 

there is no diff cover.....he would have to pull the axles and then pull the 3rd member to check....

did you put new gear lube in the rear end when you swaped it???? if not i would drain it and see if there is any gliter looking stuff in the rear end..if theres not woot for you and it need new gear lube anyways...dont forget to get something that works for the LSD

it sounds like a u-joint to me.... i could not get the video to play for some reason youtube wont play on my comp errr

 

hhhmmmm..... That does sound like a rear end humming to me..... I would do as said above, drain the diff of fliud and look for a sparkly mettalic substance to be in the gear lube

 

thankss guys.. well yeh... i drained the oil and yehh theres bits of metall... i really hope it has nothing to do with the gears thoughh.. cuz when i first got it i cleaned out the whole inside and .. thenn everything was set.. untill i went drifting and now theres particles of metal.. do you really think its the differential itself or is it the ujoints or axeL? thankss for ur input guys.. im still a newb at 16 haha just trying ta creep up to come upp..

 

well the u-joint to check out is the rear the 1 that hooks to the rear end...caz you said "sound is gone when i accelerate and it shows up when i lett off the gas" witch would make it a rear u-joint... front u-joint would be when you accelerate

cheers PaTricK

 

soo 81 gsl... if it is the rear u joint.. isnt it i cannot replace the ujoints because the u joints on the drive shaft of a 85 arent replaceable?? i dono if im right but if i cannt replace it.. my best bet is to buy a new driveshaft right?

 

Noise During Coasting:

Misadjusted drive pinion bearings
Improper backlash
Damaged gear

Per 1980 Differential Service Manual, does not take LSD units into account.

When you changed the diff, did you have it apart or did you switch it as a complete unit?

 

i switched the whole rear end.. with the calipers axles and everything.. the only thing i did was open up the pumpkin and clean out the oil and gasket maker to reseal it ... i didnt take out the gears or anything

 

ohhh and i also took out the axles

 

It did the same thing my car did. needs a fluid change.

 

DOH I need to go to bed RIGHT NOW LMAO!!! I actually had to go look under my car to check that out!! DUMBASS!!!! Shiner Bock kills braincells.

 

16 and dirifting eh. Plan on having the diff rebuilt frequently. Metal pieces in the lube means wear, what did you expect?

 

"Then I went out drifting"......

That sentence says it all.Drifting is VERY tough on any rearend,let alone a 25 year old one.
The LSD itself has no bearing to that sound since it and the differential are not doing anything when the rearend is up like that.Both tires have the same traction (none) so the carrier is spinning as a whole,the spider and side gears are not functioning.

I highly doubt its the Ujoint,thats a trademark ring and pinion humm which changes upon decel.The coast and drive sides of the diff gears are cut differently(concave/convex) so they sound different when the load is tranferred from one to the other.I would venture a guess that either your pinion or carrier bearings are shot,which is making the gear backlash flop all over the place.
Did you remove/replace the differential drive flange when you swapped rearends?
Its very tough to do that and get the pinion bearing preload right.Technically,your supposed to tear down and replace the pinion crush sleeve anytime the pinion nut is removed.The pinion bearings can exceed 5-6K RPMS, and over tightened or loose pinion bearings will destroy a gearset in very short order....

 

ahh... well i dint replace the driveshaft flange but.. like i kinda took off the nut..and yehh i dono what i did... loL but yeh i dint knoe the torque of the nut?? soo i just tightened it to what i think felt right.. soo was i supposed to replace something?? WHAT CAN I DO TO FIX THIS?? thankss guyss STEP BY STEP instructions are great and diagrams.. im really lost here.. but ill be lookin at the names of parts and stuff gahh.. thankss guyss

 

A full rearend rebuild is the only way to fix it.
Better off just sourcing a new/used third member,they drop out as a full unit and are easy to replace.Rebuilding a differential correctly requires experience and some special tools.
There is no room for error or guessing.That nut usually gets about 200+ftlbs of torque on it before the sleeve starts to crush,but with the differential assembeled,theres no way to know where your bearing preload is,so theres no way to know when to stop tightening.Just get another 3rd member from a wreckingyard or Ebay,and consider your current unit,scrap......

 

well.. yehh its been a while since i posted up again sorry.. well if you guys are still willing to helpp.. do you think you can help me fix this problem.. im thinking into rebuilding.. and i really want to learn how.. ill get tools and everythingg... CAnn you guys give me WALTHROUGHS?? or sites on helping me rebuild everything?? thanks guyss your a big help[p

 

pogi
pmd ya

 

Thats kinda like talking a doctor thru a surgery over the phone.....not really pheasible.You need to have your hands on things,in person as you assemble and measure/adjust.As stated before,its a very precise,complex assembely prceedure.

Heres an online version of the Yukon gear install guide.Print it,read it,and understand it before doing anything.Much of the guide pertains to Dana style rearends,which differ quite a bit from ours in their proceedure.The RX-7 and many Japanese rearends are more like the Ford 9" with its threaded adjusters and removable pumpkin.Once your familiar with the job,youll know which areas of the guide pertain to the RX-7 rear,and which areas do not.
Its not meant to be an end-all answer book to differential setup,but it does outline all the proceedures,types of rearend adjustements and their general,aquired knowledge from years of doing these jobs.Its very helpful for a first timer,diving into a rearend job,but....
Nothing can replace hands on experience when doing rearends.I was very hesitant at first too,it took me all day to do my first couple.Now after doing a couple dozen,Im very confident and comfortable doing them.It just takes time and know-how.....

http://www.ringpinion.com/downloads/yukoninstman.pdf#search='yukon%20gears%20%20differ ential%20guide'